Method and an Apparatus for Determining a Deviation Between an Actual Direction of a Launched Projectile and a Predetermined Direction

ABSTRACT

In a method of determining a deviation of a path of a projectile from a predetermined path, the method uses an image of a target area in which the desired path or direction is pointed out. Subsequently, the real direction or real path is determined and the deviation is determined.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.13/303,889, filed on Nov. 23, 2011, which is a divisional of U.S.application Ser. No. 11/630,904, filed on Jul. 20, 2009, now U.S. Pat.No. 8,085,188, which is a National Phase entry of PCT Application No.PCT/DK2005/000456, filed on Jul. 1, 2005, which claims priority under 35U.S.C. § 119(e) to U.S. Provisional Application No. 60/584,483, filed onJul. 2, 2004, in the U.S. Patent and Trademark Office, the entirecontents of all of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION Field of the Invention

The present invention relates to the determination of a deviationbetween an actual direction and a desired direction of a launchedprojectile, such as a golf ball I another type of sports ball, or aprojectile launched by a weapon.

More particularly, the desired direction is indicated using an image ofa target area toward which the projectile is launched or is Intended tobe launched.

SUMMARY OF THE INVENTION

In a first aspect, the invention relates to a method of determining adeviation between an actual direction of a launched projectile and apredetermined direction, the method comprising:

-   -   providing an image representing a target area,    -   indicating a position in the image, the indicated position        corresponding to a position in the target area,    -   determining the actual direction of the projectile,    -   determining a launch position of the projectile,    -   determining, from the launch position and the corresponding        position, the predetermined direction, and    -   determining the deviation between the actual direction of the        projectile and the predetermined direction.

In the present context, an image may be an actually taken image (takenusing e.g. a camera) representing the target area, or it may representmore schematically the target area or parts therein, such as a number ofelements present in the target area (trees, flags, houses or otheridentifiable elements).

The target area is normally an area, including all elements therein, asdefined either by boundaries of the image or defined by elements in orat the area. Alternatively, the target area needs not be directlydefined with boundaries but is merely an area surrounding or comprisingthe position corresponding to the indicated position.

The position in the target area normally is a position in or at theground plane of the target area. This, however, is not required. Anyposition, such as on a vertical part in the target area (such as atarget provided on a tree, a wall or the like) may be used as well asany elevated or lowered position (a roof or the like).

The correlation of the position in the image to the position in thetarget area will depend on the actual type of image and the angle fromwhich the target area is represented in the image. Normally, there is aone-to-one correspondence between positions in the image and in thetarget area, when the image is of a type representing the target areawhen viewed from a certain position. Normally, this position will be theposition, or a position close to, where the Indication is performed inorder to facilitate the selection or indication of the position in theimage. Then, the Image indicates the target area as seen from thatposition.

Alternatively, the image may represent the target area, such as seenfrom the air in the manner as maps are normally drawn.

It is noted that the projectile needs not hit or land in the target areaand it needs not be aimed at the target area. The position indicated inthe target area is in the desired direction, but the actual path desiredmay extend further or not as far as the target area.

Presently, the projectile may be any flying object, such as a sportsball (golf ball, base ball, foot ball, hand ball, basket ball), or aprojectile launched by a weapon (hand gun, machine gun, missile,grenade) or the like.

The launch position may be a position from which the projectile waslaunched either by being hit (such as by a club, a bat, a hand or afoot), released from a hand then being thrown, launched from a launchpad, such as a barrel of a weapon, a tee fixing the ball before launch,or a surface on which the projectile rests before launch.

The launch position may be determined in a number of manners. One manneris to simply assume or dictate that the launch takes place at apredetermined position or within a predetermined area.

Another manner of providing the launch position is to have the launchposition also within the Image, where a plurality of images are taken,and a difference therein is identified corresponding to the projectilehaving been launched. This difference may be the projectile missing in alater image compared to one or more images taken before launch.

The actual direction of the projectile is the direction of theprojectile while in flight. The direction may be derived from the actualpath of the projectile. The direction may be determined in apredetermined plane, in that the direction may vary in a 3-D scenario(such as the path of a golf ball) but where the most interestingdirection is that of the 3D path projected on to the ground plane.

In the present context, the deviation may be determined in any suitablemanner. This deviation may be determined in a predetermined plane inwhich also the directions have been projected, if required. This isoften a horizontal plane or a plane of the ground between the launchposition and the position corresponding to the indicated position.

The deviation may be an angular deviation between the two directions,such as in a predetermined plane. The plane may be both horizontaland/or vertical, or deviations in multiple planes may be provided.

Alternatively or in addition, the deviation may be a distance, such asin a predetermined plane, between the actual direction and thecorresponding position or between the predetermined direction and e.g. alanding point (see below) of the projectile.

In a preferred embodiment, step 1) comprises providing, with a camera,the image of the target area. The image may be provided as a videosequence, such as in real time, of the target area or may be a stillimage, such as an Image on a monitor or display, or represented as ahard copy.

Normally, the camera will be positioned close to a position where theposition in the image is indicated. This Indication may be an indicationon a display or monitor, which may be a touch pad or other touchsensitive display means, whereby indication may be performed simply bytouching the position in the image. Alternatively, a pointing device maybe used, such as a computer mouse, an optical pen, or the like.

In general, a computer or other calculating means may be used forcontrolling the determination, the indication! the providing or takingof the image, the pointing, and the like.

In one embodiment, step 1) comprises providing an image comprising aplurality of predetermined positions, and step 2) comprises indicatingone of the predetermined positions. In this manner, the correlationbetween positions in the image and the target area may be simpler andmay merely be a table describing the correlation. In fact, the positionsmay have simple numbers, and the selecting of a position may be theselection or indication, such as on a keyboard, of a number.

A particular aspect of this embodiment is one wherein the target areacomprises a plurality of predetermined elements, wherein step 1)comprises providing an image illustrating or identifying the pluralityof predetermined elements at positions corresponding to positions of theelements in the target area, and wherein step 2) comprises indicating aposition of one of the predetermined elements (or indicating the elementin the image).

The above embodiment using the providing of a number for each positionmay equally well be used here.

These positions in the image then correspond to physical elements ordemarcations in the target area. In this situation, the plurality ofpositions in the image and any corresponding physical means/elements ofthe target area may be sufficient for a user to be able to indicate adesired position, whereby the requirements to the image may be reduced.The mere structure and inter-relation between the individual elementsand positions may be sufficient for the user to identify the desiredelement/position. Thus, the image may be a more simple or schematic andonly (or at least) represent selected elements or all the elementscorresponding to the positions in the image.

Also, this means that the same set-up may be used in order to provide aplurality of predetermined directions and to launch multiple projectilesand determine multiple deviations.

In the above embodiment, a plurality of elements is visible in the imageand in the target area. Naturally, a single such element may also beused.

In this situation, the element at the position corresponding to theindicated position may have a visible part having a predetermined size.Then, step 2) could comprise:

a) determining, from the image, an angle to the indicated element and

b) determining, from the image, a distance from a predetermined positionto the indicated element by correlating an extent of the visible part inthe image with the predetermined size thereof, the correspondingposition being determined on the basis of the angle and the distance.

Knowing the angle and the distance will enable a determination of theposition of the element from the image alone. The width of thepredetermined size in the image provides the distance measure. Thevisible part may be e.g. a part at the end of a stick or pole fixed tothe ground or may be a predetermined distance from the ground to theelement.

The predetermined point may be a center of the image or a point fixed inrelation to the target area.

In an interesting embodiment, step 3) comprises determining a landingpoint of the projectile and the actual direction of the projectile isdetermined from the launch position and the landing point. Determinationof the landing point may be performed in a number of manners.

The presently preferred manner is described in the applicants co-pendingPCT/DK2005/000336, which is incorporated herein by reference.

A preferred manner of actually determining the path or direction of theprojectile is one wherein step 3) comprises:

receiving radiation transmitted by or reflected by the projectile whileit is in flight and determining, from the received radiation, adirection of the projectile.

This may be a RADAR system or any other system using radiation (orsound) for determining the position/path/direction of a projectile.

Naturally, the radiation from the projectile may be emitted from theprojectile or may be reflected there from. In the latter situation, theset-up may further comprise a step of providing radiation toward theprojectile in order to have the projectile reflect this for it to bedetermined.

In this embodiment, step 4) may comprise determining the launch positionfrom the radiation received. A number of manners exist for this. Onemanner is to determine the actual point in time of launch using e.g. amicrophone, where the launch position may then be determined from thedirection or path of the projectile.

In that situation, the positioning or position determination in theRADAR (or similar) system is preferably fixed or has a predeterminedrelation to the image or image generation in order for the launchposition (and optionally landing position) to be related to the positionidentified in the image. This relation may be provided by simply fixingthe image generation (if provided e.g. as a camera) to the RADAR system(or at least the radiation receiver(s)).

In a second aspect, the invention relates to an apparatus fordetermining a deviation between an actual direction of a launchedprojectile and a predetermined direction, the apparatus comprising:

means for providing an image representing a target area,

means for receiving an indication of a position in the image, thereceiving means being adapted to correlate the indicated position to acorresponding position in the target area,

means for determining the actual direction of the projectile,

means for determining a launch position of the projectile,

means for determining, from the launch position and the correspondingposition, the predetermined direction, and

means for determining the deviation between the actual direction of theprojectile and the predetermined direction.

Preferably, the providing means comprise a display or monitor and aprocessing unit, the display or monitor being operatively connected tothe processing unit and being adapted to provide the image, thereceiving means preferably also comprising a pointing device alsoconnected to the processing unit. This pointing device may be a computermouse, an optical pen, or the like, Alternatively, the display/monitormay be a touch pad, which then also comprises the pointing device inthat touching the display/monitor at a position will enter that positioninto the system.

In general, the means for determining the actual direction of theprojectile may comprise means for determining a landing point of theprojectile and means for determining, from the launch position and thelanding point, the actual direction of the projectile.

As mentioned above, the providing means may comprise a camera forproviding the image of the target area. This camera may be a still imagecamera or a video camera, digital cameras are widespread, but othertypes of cameras are equally useful.

In one embodiment, the providing means are adapted to provide the imagecomprising a plurality of predetermined positions, and the receivingmeans are adapted to receive an indication of one of the predeterminedpositions.

In addition to that or in combination with that, the target areapreferably comprises a plurality of predetermined elements, wherein theproviding means are adapted to provide an image illustrating oridentifying the plurality of predetermined elements at positionscorresponding to positions of the elements in the target area, and thereceiving means are then adapted to receive an indication of a positionof one of the predetermined elements. Thus, the positions couldcorrespond to physical “targets” In the target area.

In that situation, the element at the position correlated to theindicated position could have a visible part having a predeterminedsize, and the receiving means could then comprise means for:

a) determining, from the Indicated position in the image, an angle tothe indicated element and

b) determining, from the image, a distance from a predetermined positionto the indicated element by correlating an extent of the visible part inthe image with the predetermined size thereof, the receiving means beingadapted to determine the corresponding position on the basis of theangle and the distance.

The visible part may be a part at the end of a stick and may comprise avisible pattern, from which the boundaries of the visible part or fromwhich dimensions of the visible part may be determined.

As mentioned above, the means for determining the actual direction ofthe projectile may comprise means for:

receiving radiation transmitted by or reflected by the projectile whileit is in flight and

determining, from the received radiation, a direction of the projectile.

Thus, the means for determining the actual direction may be a RADARsystem or another system adapted to determine a position/path/directionfrom received radiation (or sound).

The radiation may be emitted/transmitted by the projectile or it may bereflected. In the latter situation, the apparatus may further comprisemeans for providing radiation toward the projectile.

In this embodiment, the means for determining the launch position of theprojectile may be adapted to determine the launch position from theradiation received.

In another embodiment, the means for determining the launch position ofthe projectile are adapted to assume that the launch is performed at apredetermined position. This is a simple manner of “obtaining” thatInformation.

In the embodiment where the apparatus comprises the camera, it isdesired that the determination of the launch position/landing positionand/or the path/direction/position of the projectile are correlated toeach other. This may be obtained when the camera and the radiationreceiving means are fixed in relation to each other so that theradiation receiving means are adapted to receive radiation from thetarget area viewed by the camera.

In fact, the radiation receiving means may be directed toward the targetarea so that the fields of view of the radiation receiving means and thecamera are either the same or one is comprised within the other—at leastfor the expected path or direction of the projectile.

A third aspect of the invention relates to an element for use in theabove method or for use with the above apparatus, the element comprisinga visible part having a predetermined size.

This visible part may be an element having any suitable shape, such asround, circular, square, which is visible from a distance. The elementmay have visible demarcations, such as boundaries, in order for thedistance to the element to be determinable from the extent of thesedemarcations at that distance.

The visible part may be positioned a distance, such as a predetermineddistance, from the ground and may be provided at (such as at the end of)a stick, a pole, or the like.

The visible part may be solid or may be a flag on which the demarcationsare provided. The flag may then be kept in a stretched-out manner inorder for the demarcations to be visible also in calm weather.

Additional aspects and/or advantages of the invention will be set forthin part in the description which follows and, in part, will be obviousfrom the description, or may be learned by practice of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

These and/or other aspects and advantages of the invention will becomeapparent and more readily appreciated from the following description ofthe embodiments, taken in conjunction with the accompanying drawings ofwhich:

FIG. 1 is a block diagram of the main components in the presentinvention.

FIG. 2 shows the positions of the different coordinate systems in a topview.

FIG. 3 is the process flow for selecting a target and getting ballflight data in the desired coordinate system.

FIG. 4 shows the image of a camera looking toward the target area frombehind the launch position.

FIG. 5 shows an example of a physical layout of a target that can easetarget identification.

DETAILED DESCRIPTION OF THE EMBODIMENTS

Reference will now be made in detail to the present embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to the like elementsthroughout. The embodiments are described below in order to explain thepresent invention by referring to the figures.

In the preferred embodiment of the present invention the projectile is agolf ball being launched towards a target, the image capturing device isa camera 1 and the measurement equipment to determine the actualprojectile path is a radar 2, as shown in FIG. 1. Both the image and theradar data are sent to a computer 3, which displays the image and radardata on a display 4, to ease the identification of a target in an image,a touch screen 5 is used.

Independent of the position and physical orientation of the radar, thegolf ball trajectory data, and specifically the landing point, isdesired in a coordinate system which has origo at the launch point 12and with a horizontal reference line 11 that goes through the target 10.The hereby defined coordinate system is called the golfer coordinatesystem 15, as seen in FIG. 2.

The trajectory data is measured in the radar coordinate system 16. Theimage captured by the camera 8 is defined in the camera coordinatesystem 17.

Every golf shot will typically be launched from slightly differentpositions, and also the target will often change during a golf session.This means that the position and orientation of the golfer coordinatesystem 15 is in general different for every golf shot. This illustratesthe need for an efficient way to automatically transfer measurement datafrom the radar coordinate system 16 into the golfer coordinate system15.

Previous technologies define the target by mechanically adjusting themeasurement system, e.g. the radar 2, to point directly at the target orin a predetermined offset from the target. In some technologies severalpredetermined targets positions are stored, to ease the selectionbetween these predetermined targets, Anyhow, this means that whenever anew target, the position of which is not known a priori is selected, anew mechanical adjustment would be required.

The present embodiment of the invention does not require any mechanicaladjustment as long as the desired target is in the field of view of thecamera 1 and the radar 2. This field of view is typically between 10 to30 degrees.

Previous techniques obtain the launch position by typically dictatingthe launch position to be within a predetermined very limited area, e.g.within a 20 cm diameter circle 2-4 m in front of the radar 2.

In the present embodiment of the invention, the launch position isdirectly measured by the radar 2, as being the first data pointbelonging to the golf ball flight. Other methods are outlined below.

The physical orientation and position of the camera 1 relative to theradar 2 must be known. This is most easily obtained by mounting thecamera directly on or inside the radar, so the two units will be fixedrelative to each other. The relative orientation and position isdetermined through a calibration procedure. When operating the system,the radar and camera units are assumed to be adjusted to be in level.

The procedure to select a new target in the present invention isoutlined in FIG. 3. First a picture is taken in step 19, which istypically initiated by the user. The captured image is displayed and theuser determines the position of the preferred target in the picture 21,if more targets are present. If the target is not in the field of view,it may be necessary to perform a rough alignment 27 of the camera andradar unit.

The image 28 presented to the user could look like that illustrated inFIG. 4. The horizontal line 29 in the image 28 represents the horizontalplane of the coordinate system 17, and the vertical line 30 representsthe vertical plane at the reference horizontal angle in the samecoordinate system 17. The center 31 of the camera is consequentlyreference line 9.

In the image, several targets 34, 35 will typically be displayed. Topoint out a specific target, the vertical and horizontal reference lines32, 33 are adjusted to pin point the exact location of the desiredtarget 33. This adjustment can be done manually by the user by means ofa keyboard, touch panel, mouse or similar. In some cases, see below, thesystem can also automatically detect and center the reference lines 32,33 to point at the desired target.

If the target has a predetermined shape or pattern, like in FIG. 5, thesystem can automatically center the vertical and horizontal referencelines 32, 33. If several targets are present in the target area, thetargets might preferably be of different shapes, so that the system candistinguish between them. The user will in this case either indicate thetarget number to the system, or point out the approximate location ofthe target in the image.

In the above several methods for determining the angles to the targetare outlined. To calculate the target position 10, the distance to thetarget is also required. There are several ways to determine thisdistance.

One method of determining the distance to the target is to simply havethe user enter the distance, which of course requires that the userknows this.

Another method of determining the distance to the target is to measurethe angular extent of a predetermined pattern of the target. Knowing thesize of this predetermined pattern, it is straight forward to calculatethe distance to the target. One predetermined target pattern 38, thatcan be used for this, is shown in FIG. 5, the angular dimension DHand/or DV can easily be determined from the image 28 by edge-detectiontechniques.

Once the angles and the distance to target have been determined, thetarget position can be calculated 22.

For each ball hit, the radar measures the ball flight 13. This includesmeasurements of the ball launch position 12 and the ball landing point14.

An alternative way of measuring the ball launch position is by analyzinga sequence of images 28 taken before and after launch. In this way thelaunched ball 36 can be identified in the image 28. Hereby the verticaland horizontal angle to the launch position from the camera 8 can bedetermined. The distance from the camera to the launch position can bedetermined in at least two ways.

The first method measures the angular extent of the ball in the image 28and compares this with the predetermined size of the ball. For mostsports balls, this size is very well defined.

The second method assumes that the radar 2 is at a given height abovethe launch position. Then, by knowing the vertical angle to the launchposition from above, the distance can be calculated directly using thesimple trigonometric relation between the parameters.

By knowing the launch position 12 and the target position 10, the golfercoordinate system 15 is determined.

The radar will measure the ball flight 13 in the radar coordinate system16. These data are then coordinate transferred 25 in to the golfercoordinate system 15 through a 3 dimensional translation and rotation.

Finally the ball flight data are presented to the user 26.

Although a few embodiments of the present invention have been shown anddescribed, it would be appreciated by those skilled in the art thatchanges may be made in this embodiment without departing from theprinciples and spirit of the invention, the scope of which is defined inthe claims and their equivalents.

1-10. (canceled)
 11. A method for tracking a projectile comprising:providing an image representing a target area, the image identifying anelement at a position corresponding to a position of the element in thetarget area; defining an image coordinate system defining the positionof the element in the image; identifying a position of the element inthe image coordinate system; determining, using a radar, at least aportion of a trajectory of the projectile; identifying a launch positionof the projectile; generating a target coordinate system centered at thelaunch position based on a first axis extending from the launch positionthrough the element and a second axis perpendicular to the first axispassing through the launch position; and mapping the position of theprojectile in the target coordinate system.
 12. The method according toclaim 11, wherein the target coordinate system includes a third axisperpendicular to the first and second axes and passing through thelaunch position;
 13. The method of claim 12, wherein the third axis isvertical.
 14. The method of claim 12, wherein the step of determiningthe launch position comprises extrapolating the trajectory back in timeto a location corresponding to known characteristics of the launch. 15.The method of claim 11, wherein the element has a visible part havingknown characteristics, the method further comprising automaticallyidentifying the element based on the known characteristics anddetermining, from the position of the element in the image, an angle tothe element.
 16. The method of claim 15, further comprising determiningautomatically, from the image, a distance from an imager producing theimage to the element by correlating a dimension of a visible part of theelement in the image with a known size of the visible part.
 17. Themethod of claim 11, wherein the step of determining the launch positioncomprises assuming that the launch position is at a predeterminedposition.
 18. An apparatus for determining a deviation between adirection of a launched projectile and a predetermined direction, theapparatus comprising: a camera providing an image representing a targetarea, the image identifying an element at a position corresponding to aposition of the element in the target area; an indication unit receivingan indication of the position of the element in the image; a radargenerating radar data corresponding to movement of the projectilethrough the target area; and a processing unit identifying at least apart of a trajectory of the projectile based on the radar data, theprocessing unit determining a launch position of the projectile based onthe radar data, the processing unit defining an image coordinate systemdefining positions of the elements in the image and generating a targetcoordinate system based on a first axis extending from the launchposition through the element and a second axis perpendicular to thefirst axis passing through the launch position, the processing unitmapping the position of the projectile in the target coordinate system.19. The apparatus of claim 18, wherein the target coordinate systemincludes a third axis perpendicular to the first and second axes andpassing through the launch location.
 20. The apparatus of claim 19,wherein the third axis is vertical.
 21. The apparatus of claim 18,wherein the processing unit determines the launch position byextrapolating the trajectory of the projectile back in time to alocation corresponding to known characteristics of a launch.
 22. Theapparatus of claim 18, wherein the element has a visible part havingknown characteristics and wherein the processing unit automaticallyidentifies the element based on the known characteristics of the visiblepart and, based on the position of the element in the image, identifiesan angle from the camera to the element.
 23. The apparatus of claim 22,wherein the processing unit determines automatically a distance from thecamera to the element by correlating a dimension in the image of thevisible part of the element with a known size of the visible part of theelement.
 24. The apparatus of claim 18, wherein the processing unitdetermines the launch position based on an assumed launch position.